KR20100004727A - Novel benzoimidazole derivatives and organic electroluminescent device comprising the same - Google Patents

Abstract

PURPOSE: An organic electroluminescent device containing benzoimidazole derivative is provided to has low driving voltage and high fluorescence efficiency. CONSTITUTION: A benzoiminidazole derivative is denoted by chemical formula 1. In chemical formula 1: X is N-R6, S or O; and R1 is straight or branched aromatic carbon hydrogen which is substituted or unsubstituted, or RaNRbRc or -RaRbSiRcRd. An organic electroluminescent device comprises anode, cathode and organic layer between the electrodes.

Description

Novel benzoimidazole derivatives and organic electroluminescent devices comprising the same {NOVEL BENZOIMIDAZOLE DERIVATIVES AND ORGANIC ELECTROLUMINESCENT DEVICE COMPRISING THE SAME}

The present invention relates to an organic electroluminescent device (OLED) comprising multiple organic layers between an anode and a cathode.

Recently, the organic electroluminescent device capable of low voltage driving with self-luminous type has better viewing angle, contrast ratio, etc. than liquid crystal display (LCD), which is the mainstream of flat panel display devices, and is light and thin because no backlight is required. In terms of power consumption, the color reproduction range is attracting attention as a next-generation display device.

In general, an organic electroluminescent device has a structure including a cathode (electron injection electrode) and an anode (hole injection electrode), and an organic layer between the two electrodes. In this case, the organic layer may be a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL) and / or an electron injection layer, in addition to a light emitting layer (LEL). And an electron injection layer (EIL), and may further include an electron blocking layer (EBL) or a hole blocking layer (HBL) due to light emission characteristics of the light emitting layer.

When an electric field is applied to the organic electroluminescent device having such a structure, holes are injected from the anode, electrons are injected from the cathode, and holes and electrons are recombined in the emission layer through the hole transport layer and the electron transport layer, respectively, thereby emitting light. form exitons). The formed light exciton emits light while transitioning to the ground state.

However, when fabricating an organic electroluminescent device using currently known light emitting materials, there are many difficulties in practical use due to low efficiency and short lifespan. Therefore, efforts have been made to develop organic electroluminescent devices having low driving voltage, high efficiency and long life using various kinds of materials.

Among them, examples of using a benzoimidazole derivative as an electron transporting material are disclosed in US Patent No. 5766779 and Korean Patent No. 10-0691543. However, organic electroluminescent devices using these compounds do not have sufficient luminescence efficiency and therefore need to be further improved.

Accordingly, it is an object of the present invention to provide an organic electroluminescent device having excellent driving voltage, high luminous efficiency and luminous luminance, and a long lifetime.

In order to achieve the above object, the present invention provides a compound represented by the following formula (1).

Formula 1

Where

X is NR ₆ , S or O;

R ₁ is a straight or branched C _4-30 aromatic hydrocarbon substituted or unsubstituted by one or more substituents, or R _a NR _b R _c or -R _a R _b SiR _c R unsubstituted or substituted by one or more substituents; _d ;

R ₂ to R ₆ are each independently hydrogen, substituted by one or more substituents or unsubstituted linear or branched C _{1 -22} aliphatic hydrocarbon group, substituted by one or more substituents or unsubstituted C _{4 -30} aromatic hydrocarbon group, halogen _{, -C (= O) -R a} , -C (= O) -OR a, -OR a, -C (= O) -NR a R b, optionally substituted by one or more substituents or unsubstituted NR _a R _b , or cyano;

In this case, the substituent is substituted by halogen or unsubstituted linear or branched C _1-22 aliphatic hydrocarbons, C _1-22 aliphatic hydrocarbons or C _4-30 heteroaryl or substituted by an aromatic hydrocarbon group unsubstituted aromatic C _{4 -30} Hydrocarbon, halogen, -C (= 0) -R _e , -C (= 0) -OR _e , -OR _e , -NR _e R _f , or cyano;

Wherein R _a to R _f are each independently hydrogen, C _1-22 alkyl, or C _4-30 aromatic hydrocarbon.

The organic electroluminescent device according to the present invention has a low driving voltage, has a high luminous efficiency and a luminous brightness, and can significantly improve driving voltage, luminous efficiency and lifespan characteristics compared to the conventional organic electroluminescent device.

Hereinafter, the present invention will be described in more detail.

The derivative according to the present invention has an asymmetric structure, and two benzoimidazoles have an asymmetric structure, or benzoimidazole and benzothiazole or benzoimidazole and benzoxazole have asymmetric structure.

In Formula 1, R ₁ is a straight or branched C _4-30 aromatic hydrocarbon substituted or unsubstituted by one or more substituents, or R _a NR _b R _c or -R _a unsubstituted or substituted by one or more substituents R _b SiR _c R _d , specifically, an aromatic heterocycle or an aromatic ring including phenyl, naphthyl, anthracenyl, triphenylamine, tetraphenylsilane, unsubstituted or substituted by one or more substituents.

In Formula 1, R ₂ to R ₆ are each independently hydrogen, a straight or branched C _1-22 aliphatic hydrocarbon unsubstituted or substituted by one or more substituents, C _4- unsubstituted or substituted by one or more substituents. ₃₀ aromatic hydrocarbon, halogen, -C (= 0) -R _a , -C (= 0) -OR _a , -OR _a , -C (= 0) -NR _a R _b , substituted or unsubstituted by one or more substituents Ring NR _a R _b , or cyano, specifically alkyl, alkenyl, alkynyl, phenyl, naphthyl, anthracenyl.

In Formula 1, the substituent is C _4- unsubstituted or substituted by a straight or branched C _1-22 aliphatic hydrocarbon, C _1-22 aliphatic hydrocarbon, or C _4-30 heteroaromatic hydrocarbon unsubstituted or substituted by halogen. ₃₀ aromatic hydrocarbon, halogen, -C (= 0) -R _e , -C (= 0) -OR _e , -OR _e , -NR _e R _f , or cyano.

In Formula 1, R _a to R _f are each independently hydrogen, C _1-22 alkyl, or C _4-30 aromatic hydrocarbon.

More preferably, Formula 1 is represented by A-ph-B-C, and specific examples are described below. But it is not limited to this.

Y below is S or O.

On the other hand, the organic electroluminescent device of the present invention contains a compound represented by the formula (1) in the organic layer, the structure of such an organic electroluminescent device is not particularly limited and can be configured arbitrarily. For example, anode / light emitting layer / electron transport layer / electron injection layer / cathode, anode / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode, anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / Cathode or anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / cathode and the like. In addition, the constituent material of each layer is not specifically limited, Conventionally, the organic light emitting material for OLED can be used as it is. The compound represented by Formula 1 of the present invention is preferably contained in the light emitting layer or the electron transport layer.

In order to manufacture the organic electroluminescent device according to the present invention, first, a positive electrode is coated on a surface of a substrate by a conventional method to form a positive electrode. At this time, the substrate used is preferably a glass substrate or a transparent plastic substrate excellent in transparency, surface smoothness, ease of handling and waterproofness. In addition, as the material for the positive electrode, transparent indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO ₂ ), zinc oxide (ZnO), or the like having a large work function may be used.

Next, a hole injection layer is formed on the surface of the anode by vacuum thermal evaporation or spin coating of the hole injection layer material in a conventional manner. At this time, the hole injection layer material is not particularly limited, but copper phthalocyanine (CuPc), 4,4 ', 4 "-tris (N-carbazolyl) triphenylamine (TCTA), 4,4', 4"- Tris (N- (2-naphthyl) -N-phenylamino) -triphenylamine (2-TNATA) or 4,4 ', 4 "-tris (3-methylphenylamino) triphenylamine (m-MTDATA) Can be used.

A hole transport layer is formed on the surface of the hole injection layer by vacuum thermal evaporation or spin coating of the hole transport layer material in a conventional manner. In this case, the hole transport layer material is not particularly limited, but 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPB) may be used.

The light emitting layer is formed on the surface of the hole transport layer by vacuum thermal evaporation or spin coating of a light emitting layer material in a conventional manner. In this case, the host material is not particularly limited as the host material, and tris (8-quinolinolato) aluminum (Alq ₃ ) or 9,10-di (naphthalen-2-yl) anthracene (ADN) may be used. Can be.

The compound of Formula 1 may be used as a host used with a light emitting dopant in the light emitting layer material. At this time, the dopant that can be used with the compound of Formula 1 is not particularly limited, IDE102, IDE105, BD-052X or C-545T (2,3,6,7 as a green fluorescent dopant) available from Idemitsu as a fluorescent dopant -Tetrahydro-1,1,7,7-tetramethyl-1H, 5H, 11H-10- (2-benzothiazolyl) quinolizino- [9,9a, 1gh] coumarin) as a phosphorescent dopant 2-phenylpyridine) iridium (III) (Ir (ppy) ₃ ), iridium (III) bis [(4,6-difluorophenyl) pyridinato-N, C-2 '] picolinate (FIrpic) (See Chihaya Adachi etc. Appl. Phys. Lett ., 2001 , 79 , 3082-3084), platinum (II) octaethylporphyrin (PtOEP) or TBE002 (Kobiion) and the like can be used.

The electron transport layer is formed on the surface of the light emitting layer by vacuum thermal lamination or spin coating in a conventional manner to form an electron transport layer. In this case, the electron transporting material used may be a compound represented by Formula 1 or tris (8-quinolinolato) aluminum (Alq ₃ ) or 2- (4-biphenolyl) -5-phenyl-1,3,4- Oxadiazole (PBD) can be used.

Optionally, a hole blocking layer may be formed between the light emitting layer and the electron transport layer, and the hole blocking layer material used may include 2,9-dimethyl-4,7-diphenyl- [1,10] phenanthroline ( BCP), bis (8-hydroxy-2-methylquinolinolato) -aluminum biphenoxide (BAlq) or 2,2 ', 2 "-(1,3,5-benzenetriyl) tris (1- Phenyl-1H-benzimidazole) (TPBI) can be used.

The electron injection layer material is formed on the surface of the electron transport layer by vacuum thermal deposition or spin coating in a conventional manner to form an electron injection layer. In this case, the electron injection layer material used is not particularly limited, and materials such as LiF, Liq (8-hydroxyquinolinolato) lithium), Li ₂ O, BaO, NaCl, or CsF may be used.

Finally, a negative electrode is formed on the surface of the electron injection layer by vacuum thermal vapor deposition in a conventional manner. In this case, the material used may be a metal, alloy or electrically conductive compound having a small work function, specifically, lithium (Li), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), Magnesium (Mg), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), or the like can be used.

Because the material of the anode and cathode can be selected so that the work function of the anode is larger than the work function of the cathode (for example, in the case of a front light emitting device using Al for the anode and ITO for the cathode), the anode material and the cathode material are It is not limited only to the above-mentioned materials.

Although the thickness of each layer is not specifically limited, Although it can select suitably according to a situation, the range of 1 nm-1 micrometer is preferable normally.

The present invention will be described in more detail with reference to the following examples. However, the following examples are only examples of the present invention and the present invention is not limited thereto.

Example  1: Preparation of Compound of Formula 3-6

Step 1-1: Synthesis of Compound of 3-6-A

4-bromobenzoyl chloride (82.0 mmol, 18 g) was added to a 500 ml round bottom flask, dried in vacuo, and placed in a nitrogen atmosphere. Then, 300 ml of dimethylacetamide was added and stirred at 0 ° C. N-phenyl-benzene-1,2-diamine (74.3 mmol, 13.7 g) dissolved in a small amount of dimethylacetamide was added to the solution using a syringe and stirred for 24 hours. After the reaction was completed, pyridine (111.5 mmol, 9.0 ml) and 50 ml of water were added thereto and stirred to form a white precipitate. The resulting precipitate was washed with methanol with filtration to afford the title compound.

Yield: 85% (23.2 g), white powder

Step 1-2: Synthesis of Compound of 3-6-B

Into a 500 ml round bottom flask was placed 4-bromo-N- (2-phenylamino-phenyl) -benzamide (62.6 mmol, 23 g), 300 ml of toluene and p-toluene sulfonic acid monohydrate (31.3 mmol, 5.9 g). Excess magnesium sulfate was added to remove the water, followed by stirring at 110 ° C. for 4 hours. After completion of the reaction, washing with ether and hexane while filtration gave the title compound.

Yield: 75% (16.4 g), white powder

Step 1-3: Synthesis of Compound of Formula 3-6-C

9,10-dibromo-anthracene (89.2 mmol, 30 g), 2-phenyl-1H-benzoimidazole (89.2 mmol, 17.3 g), copper iodide (8.92 mmol, 1.7 g) and 9, in a 500 ml round bottom flask 10-phenanthroline (9,10-phenanthroline) (16.5 mmol, 3 g) was added to 2M cesium carbonate and dimethylformamide (DMF) solution and heated to reflux for two days. After the reaction was completed, the resulting solid was filtered, the remaining filtrate was extracted with methylene chloride and water, dried over magnesium sulfate and concentrated. Extraction by silica gel column chromatography gave the title compound.

Yield: 40% (16g), yellow powder

Step 1-4: Synthesis of Compound 3-6-D Compound

1- (10-Bromo-anthracene-9-yl) -2-phenyl-1H-benzoimidazole (35.6 mmol, 16 g) was added to a 500 ml round bottom flask, followed by vacuum drying. Purified tetrahydrofuran (THF) 300 ml was added and the temperature was reduced to -78 ° C while the solution was stirred. 2.5M n-butyl lithium solution (42.7 mmol, 17 mL) in hexane was added to the solution, followed by stirring for 1 hour. Then, isopropyl borate (53.4 mmol, 12.3 ml) was added thereto and stirred for 2 hours. After the reaction, 2.5 M hydrochloric acid (100 mL) was added and stirred for 1 hour. Then, the mixture was extracted with methylene chloride and water and then reprecipitated with hexane to obtain the title compound.

Yield: 70% (10.3 g), yellow powder

Step 1-5: Synthesis of Compound of Formula 3-6

In a 500 ml round bottom flask, 3-6-B compound (24.1 mmol, 8.4 g) prepared in step 1-2, 3-6-D compound (24.1 mmol, 10 g) prepared in step 1-4, Tetrakistriphenylphosphinopalladium (1.2 mmol, 1.4 g) and potassium carbonate (48.2 mmol, 6.7 g) were added to 300 ml of THF and 100 ml of water and stirred at 80 ° C. The resulting solid was filtered and washed with acetone and water to give a compound.

Yield: 50% (15.1 g)

¹ H-NMR (CDCl ₃ ) δ 7.9 (d, 4H), 7.7 (d, 4H), 7.5 (d, 6H), 7.4 (m, 6H), 7.3 (m, 9H), 7.2 (t, 1H)

Example  2: Preparation of Compound of Formula 3-10

Step 2-1: Synthesis of Compound of Formula 3-10-A

Magnesium (382 mmol, 9.2 g) was added to the dried 1 L round bottom flask and dried. After the nitrogen atmosphere was added, 100 ml of THF was added to the magnesium soak and stirred. Bromo-benzene (191 mmol, 30 g) dissolved in THF was added to the reaction solution, followed by stirring for 1 hour to prepare a benzenemagnesium bromide reagent. Then, 2,6-dibromo-anthraquinone (63.6 mmol, 23.3 g) was put into a 1 L round bottom flask, and vacuum dried, 500 mL of purified THF was added thereto, and the resulting solution was stirred at -78 ° C. Reduced. After the temperature of the solution was reduced to −78 ° C., a benzenemagnesium bromide solution prepared above was added and stirred for 16 hours. After the reaction was completed, the solvent was removed and extracted with water and methylene chloride. The extracted organic layer was concentrated to a 2 L round bottom flask, 1000 mL of acetonitrile was added thereto, tin chloride (159 mmol, 35 g) was added thereto, and the mixture was stirred at 80 ° C. for 3 hours. Acetonitrile was removed, extracted with water and methyl chloride, and the organic layer was concentrated. Dichloromethane and acetonitrile were added to the obtained mixture and recrystallized to obtain the title compound.

Yield: 65% (20 g)

Step 2-2: Synthesis of Compound of Formula 3-10-B:

It was carried out in the same manner as the synthesis method of the compound 3-6-C.

Yield: 35% (8.6 g)

Step 2-3: Synthesis of Compound of Formula 3-10-C:

It was carried out in the same manner as the synthesis method of the compound 3-6-D.

Yield: 70% (5.66g)

Step 2-4: Synthesis of Compound of Formula 3-10

In a 250 ml round bottom flask, 3-6-B compound (9.9 mmol, 3.4 g) prepared in step 1-2, 3-10-C compound (9.9 mmol, 5.6 g) prepared in step 2-4, tetra Keystriphenylphosphinopalladium (0.5 mmol, 0.57 g) and potassium carbonate (19.8 mmol, 2.73 g) were added, and 150 ml of THF and 50 ml of water were added thereto, followed by stirring at 80 ° C. The resulting solid was filtered and washed with acetone and water to give a compound.

Yield: 60% (4.7 g)

¹ H-NMR (CDCl ₃ ) δ 8.1 (s, 1H), 8.0 (s, 1H), 7.9 (d, 2H), 7.7 (d, 4H), 7.6 (d, 1H), 7.5 (m, 10H) , 7.5 (d, 1H), 7.3 (m, 6H), 7.3 (m, 9H), 7.2 (t, 3H)

Example  3: Preparation of the compound of Formula 7-6

Step 3-1: Synthesis of Compound of Formula 7-6-A

It was carried out in the same manner as the synthesis method of the compound 3-6-C.

Step 3-2: Synthesis of Compound of Formula 7-6-B

It was carried out in the same manner as the synthesis method of the compound 3-6-D.

Step 3-3: Synthesis of Compound of Formula 7-6

In a 500 ml round bottom flask, 7-6-B compound (24.1 mmol, 10 g), 2- (4-bromo-phenyl) -benzothiazole (24.1 mmol, 7 g) and tetraquistri prepared in step 3-2 were prepared. Phenylphosphinopalladium (1.2 mmol, 1.4 g) and potassium carbonate (48.2 mmol, 6.7 g) were added thereto, and 300 ml of THF and 100 ml of water were added thereto, followed by stirring at 80 ° C. The resulting solid was filtered and washed with acetone and water to give a compound.

Yield: 50% (7 g)

¹ H-NMR (CDCl ₃ ) δ 8.2 (d, 2H), 7.9 (d, 4H), 7.7 (d, 6H), 7.5 (m, 4H), 7.4 (m, 6H), 7.2 (t, 2H) , 7.2 (t, 1H)

Example  4: Preparation of Compound of Formula 7-10

Step 4-1: Synthesis of Compound of Formula 7-10-A

It was performed in the same manner as the synthesis method of the compound of Formula 3-10-A.

Step 4-2: Synthesis of Compound of Formula 7-10-B

It was performed in the same manner as the synthesis method of the compound of Formula 3-10-B.

Step 4-3: Synthesis of Compound of Formula 7-10-C:

It was performed in the same manner as the synthesis method of the compound of Formula 3-10-C.

Step 4-4: Synthesis of Compound of Formula 7-10

In a 500 ml round bottom flask, 7-10-C compound (17.6 mmol, 10 g), 2- (4-bromo-phenyl) -benzothiazole (17.6 mmol, 5.1 g), tetra Keystriphenylphosphinopalladium (0.88 mmol, 1.0 g) and potassium carbonate (35.2 mmol, 4.86 g) were added, and 300 ml of THF and 100 ml of water were added thereto, followed by stirring at 80 ° C. The resulting solid was filtered and washed with acetone and water to give a compound.

Yield: 65% (8.3 g)

¹ H-NMR (CDCl ₃ ) δ 8.2 (d, 1H), 8.1 (d, 3H), 7.9 (s, 2H), 7.7 (d, 4H), 7.5 (m, 10H), 7.4 (d, 6H) , 7.4 (d, 1 H), 7.3 (m, 6 H)

Example  5: organic according to the invention Electroluminescence  Device fabrication and test

A 5 mm x 5 mm x 1 mm glass substrate having ITO formed thereon was prepared as a transparent support substrate, and a 60 nm hole injection layer (2-TNATA: 4,4 ', 4 "-tris (N- (2-nap) was formed thereon. Thi) -N-phenyl-amino) -triphenylamine), 30 nm hole transport layer (NPB: 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), 45 nm Alq ₃ and C-545T doped light emitting layer (C-545T: 2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H, 5H, 11H-10- (2-benzothiazolyl ), An organic field is deposited by sequentially depositing a quinolizino- [9,9a, 1gh] coumarin), an electron transport layer of 25 nm (compound represented by formula 3-6), an electron injection layer of 1 nm (LiF), and an aluminum cathode of 150 nm. A light emitting device was produced.

For the manufactured organic electroluminescent device, the results of measuring device characteristics are summarized in Table 1 below.

Example  6: organic according to the invention Electroluminescence  Device fabrication and test

In Example 1 to prepare a device using compound 3-10 instead of compound 3-6 and the results of measuring the properties are summarized in Table 1 below.

Example  7: organic according to the invention Electroluminescence  Device fabrication and test

In Example 1 to manufacture a device using compound 7-6 instead of compound 3-6 and the results of the measurement of the characteristics are summarized in Table 1 below.

Example 8 Fabrication and Test of Organic Electroluminescent Device According to the Present Invention

In Example 1 to prepare a device using compound 7-10 instead of compound 3-6 and the results of the measurement of the characteristics are summarized in Table 1 below.

Comparative example  1: organic Electroluminescence  Device fabrication and test

Instead of compound 3-6 in Example 1 using an Alq ₃ represented by the following formula to manufacture a device measuring the properties and the results are summarized in Table 1 below.

Comparative example  2: organic Electroluminescence  Device fabrication and test

In Example 1, instead of compound 3-6, the device was fabricated using TPBi described in US Pat. No. 5,564,48, which is represented by the following Chemical Formula 2, and the characteristics thereof were summarized in Table 1 below.

As can be seen from the results of Table 1, the organic electroluminescent devices of Examples 1 to 4, which contain the compound of the present invention, have a lower driving voltage and emit light than the organic electroluminescent devices of Comparative Examples 1 and 2. It can be seen that the efficiency is excellent.

Claims (6)

Benzimidazole derivatives represented by the following formula (1): Formula 1

Where X is NR ₆ , S or O; R ₁ is a straight or branched C _4-30 aromatic hydrocarbon substituted or unsubstituted by one or more substituents, or R _a NR _b R _c or -R _a R _b SiR _c R unsubstituted or substituted by one or more substituents; _d ; R ₂ to R ₆ are each independently hydrogen, substituted by one or more substituents or unsubstituted linear or branched C _1-22 aliphatic hydrocarbon group, substituted by one or more substituents or unsubstituted C _{4 -30} aromatic hydrocarbon group, halogen _{, -C (= O) -R a} , -C (= O) -OR a, -OR a, -C (= O) -NR a R b, optionally substituted by one or more substituents or unsubstituted NR _a R _b , or cyano; In this case, the substituent is substituted by halogen or substituted by an unsubstituted straight-chain or branched C _1-22 hydrocarbon group not bangjok, C _1-22 aliphatic hydrocarbons or C _4-30 heteroaromatic hydrocarbon or unsubstituted C _{4 -30} ring Aromatic hydrocarbon, halogen, -C (= 0) -R _e , -C (= 0) -OR _e , -OR _e , -NR _e R _f , or cyano; Wherein R _a to R _f are each independently hydrogen, C _1-22 alkyl, or C _4-30 aromatic hydrocarbon. The method of claim 1, X is NR ₆ ; R ₁ is an aromatic heterocycle or an aromatic ring selected from the group consisting of straight or branched phenyl, naphthyl, anthracenyl, triphenylamine and tetraphenylsilane unsubstituted or substituted by one or more substituents; R ₂ to R ₆ are each independently hydrogen; _Straight chain or branched C _1-22 alkyl, alkenyl or alkynyl unsubstituted or substituted by one or more substituents; Phenyl, naphthyl or anthracenyl, unsubstituted or substituted by one or more substituents; Or NR _a R _b unsubstituted or substituted by one or more substituents; Wherein the substituents are substituted by halogen or unsubstituted linear or branched C _1-22 aliphatic hydrocarbons, C _1-22 aliphatic hydrocarbons or C _4-30 heteroaryl or substituted by an aromatic hydrocarbon group unsubstituted C _4-30 aromatic Hydrocarbon, halogen, -C (= 0) -R _e , -C (= 0) -OR _e , -OR _e , -NR _e R _f , or cyano; Wherein R _a , R _b , R _e and R _f are each independently hydrogen, C _1-22 alkyl, or C _4-30 aromatic hydrocarbons, Benzimidazole derivatives. The method of claim 1, X is S; R ₁ is an aromatic heterocycle or an aromatic ring selected from the group consisting of straight or branched phenyl, naphthyl, anthracenyl, triphenylamine and tetraphenylsilane unsubstituted or substituted by one or more substituents; R ₂ to R ₅ are each independently hydrogen; Straight or branched C _1-22 alkyl, alkenyl or alkynyl unsubstituted or substituted by one or more substituents; Phenyl, naphthyl or anthracenyl, unsubstituted or substituted by one or more substituents; Or NR _a R _b unsubstituted or substituted by one or more substituents; Wherein the substituents are substituted by halogen or unsubstituted linear or branched C _1-22 aliphatic hydrocarbons, C _1-22 aliphatic hydrocarbons or C _4-30 heteroaryl or substituted by an aromatic hydrocarbon group unsubstituted C _4-30 aromatic Hydrocarbon, halogen, -C (= 0) -R _e , -C (= 0) -OR _e , -OR _e , -NR _e R _f , or cyano; Wherein R _a , R _b , R _e and R _f are each independently hydrogen, C _1-22 alkyl, or C _4-30 aromatic hydrocarbons, Benzimidazole derivatives. The method of claim 1, X is O; R ₁ is an aromatic heterocycle or an aromatic ring selected from the group consisting of straight or branched phenyl, naphthyl, anthracenyl, triphenylamine and tetraphenylsilane unsubstituted or substituted by one or more substituents; R ₂ to R ₅ are each independently hydrogen; Straight or branched C _1-22 alkyl, alkenyl or alkynyl unsubstituted or substituted by one or more substituents; Phenyl, naphthyl or anthracenyl, unsubstituted or substituted by one or more substituents; Or NR _a R _b unsubstituted or substituted by one or more substituents; Wherein the substituents are substituted by halogen or unsubstituted linear or branched C _1-22 aliphatic hydrocarbons, C _1-22 aliphatic hydrocarbons or C _4-30 heteroaryl or substituted by an aromatic hydrocarbon group unsubstituted C _4-30 aromatic Hydrocarbon, halogen, -C (= 0) -R _e , -C (= 0) -OR _e , -OR _e , -NR _e R _f , or cyano; Wherein R _a , R _b , R _e and R _f are each independently hydrogen, C _1-22 alkyl, or C _4-30 aromatic hydrocarbons, Benzimidazole derivatives. An organic electroluminescent device having an organic layer consisting of at least one layer between an anode, a cathode and two electrodes, wherein at least one of the organic layers comprises the benzoimidazole derivative according to any one of claims 1 to 4. The method of claim 5, wherein The organic electroluminescent device comprising the light emitting layer and the electron transport layer.